Hierarchical Co₃(PO₄)₂/CuI/g-C_nH_2n–2 S-Scheme Heterojunction for Efficient Photocatalytic Hydrogen Evolution

Abstract

Graphdiyne (GD), a new type of carbon allotrope formed by sp and sp 2 hybrid carbon atoms, has attracted wide attention due to its high π-conjugation degree, special band structure, and uniformly distributed pores. In traditional synthesis methods, hexaethylbenzene was coupled on the substrate catalytic material (copper foil or foamed copper) to generate graphdiyne. In this work, CuI was used as the substrate catalytic material, and the CuI-GD composite was synthesized by cross-coupling in the pyridine solution of hexaethylbenzene. For the first time, Co 3 (PO 4 ) 2 was modified by the CuI-GD composite material to prepare a Co 3 (PO 4 ) 2 /CuI-GD S-scheme heterojunction catalyst, which avoided the complicated process of removing the substrate catalytic material. Under the action of the internal electric field, electrons are induced to move quickly and directionally, and the powerful photogenerated electrons in the conduction band (CB) of GD and the holes in the valence band (VB) of CuI are retained to participate in the photocatalytic reaction. These advantages were combined with the high-energy acetylene bond in GD, which accelerated the catalytic reaction of the Co 3 (PO 4 ) 2 /CuI-GD heterostructure. Electrochemical and fluorescence analysis showed that Co 3 (PO 4 ) 2 / CuI-GD has faster electron and hole separation efficiency, lower hydrogen evolution overpotential, and higher carrier utilization. Therefore, Co 3 (PO 4 ) 2 /CuI-GD exhibited good hydrogen evolution activity. This work shows that GD has broad prospects in designing high-performance photocatalyst systems.

Graphdiyne(CnH2n‐2)‐Based NiCo LDH – Graphdiyne – CuI Double S‐Scheme Heterojunction For Efficient Photocatalytic Hydrogen Production**

“…The XPS of Cu 2p is shown in Figure 5E and S5, showing two distinctive characteristic peaks at 932.74 eV (Cu 2p 3/2 ) and 952.53 eV (Cu 2p 1/2 ) (Figure 5E). The elemental composition and valence states in Figure S5 are analyzed by the same method [30] . The XPS of I 3d is shown in Figure 5F and S6, showing two distinctive characteristic peaks at 619.84 eV (I 3d 5/2 ) and 631.33 eV (I 3d 3/2 ) (Figure 5F).…”

“…The elemental composition and valence states in Figure S5 are analyzed by the same method. [30] The XPS of I 3d is shown in Figure 5F and S6, showing two distinctive characteristic peaks at 619.84 eV (I 3d 5/2 ) and 631.33 eV (I 3d 3/2 ) (Figure 5F). [32] The elemental composition and valence states in Figure S6 are analyzed by the same method.…”

“…[25][26][27] What's more, graphdiyne unique inhomogeneous electronic structure and controllable all-carbon skeleton endow it with the advantages of large specific surface area, high interfacial reactivity, high room temperature carrier mobility, and excellent semiconducting properties. [28][29][30][31] Therefore, it exhibits excellent optical, electrical, magnetic and catalytic properties and can be used in various fields such as optoelectronics, semiconductors and solar cells. At present, Graphdiyne is not widely used in the field of photocatalytic hydrogen precipitation.…”

“…Graphdiyne is formed by inserting alkyne bonds between benzene rings, and has a triangular pore‐like structure connected by sp 2 carbon and sp carbon [25–27] . What's more, graphdiyne unique inhomogeneous electronic structure and controllable all‐carbon skeleton endow it with the advantages of large specific surface area, high interfacial reactivity, high room temperature carrier mobility, and excellent semiconducting properties [28–31] . Therefore, it exhibits excellent optical, electrical, magnetic and catalytic properties and can be used in various fields such as optoelectronics, semiconductors and solar cells.…”

A mechanochemically prepared graphdiyne (CnH2n−2) based Cu3P@GDY p–n heterojunction for efficient photocatalytic hydrogen evolution

“…According to the analysis the positive slope of the curve corresponds to an n-type semiconductor, GDY has the characteristics of an n-type semiconductor, and Cu 3 P has the characteristics of a p-type semiconductor. 73,74 The E  for GDY and Cu 3 P is estimated to be À0.58 V and 0.92 V. In Fig. 9c, the "Vshaped" Mott-Schottky diagram of CPG2 further conrmed the construction of a p-n type heterojunction, and CPG2 showed at band potentials of 0.32 and 1.38 V, indicating that the Fermi level of n-type GDY decreased with the increase of the energy band of hybrid materials while the Fermi energy level of p-type Cu 3 P increases with the increase of the energy band of the hybrid material.…”